I've flown quite a few times over the past 2 years in CE. Major difference is the hot (LCY) v cold (LGW/LHR) food on the return flight to London. Whether it's the dreaded 3 prawner or not, it's a combination of the crew / seating / fellow passengers that make you smile or scowl on exit. In general, I really cannot say that a LCY crew is, on average, better than a LGW or LHR crew.